I've done some tropical island hacking (solo) and it worked really well for me.
The longest I did was 3 weeks on Koh Phi Phi in Thailand. I had a nice discrete problem: write Forth drivers for all the interesting hardware in a little ARM SoC. Blog at the time: <a href="http://goo.gl/V9qGx" rel="nofollow">http://goo.gl/V9qGx</a>
I can say that:
Finding a place to sleep, entertainment (snorkel, scuba, etc), and food were all easy problems.
Finding a place to work can be harder: power, internet, quiet, table/desk all in one place. (Maybe you need to borrow a house?)
Three weeks was enough for me: then I wanted a dose of civilization and city life, hard though this was to imagine on day #1. Maybe it's different with more people.<p>Can you start simple, with just a few people and lasting until they get bored, and scale it up gradually perhaps?